1. Field of the Invention
The present invention relates generally to a Grid Rail (GRAIL) high productivity, high density container storage yard system located adjacent to a facility for loading and unloading containers. More particularly, the subject invention pertains to a system as described which is designed for operation in any typical marine terminal container loading and unloading environment throughout the world and which is provided with an integrated container handling system for transporting containers between a stacked container storage yard and one or more shore cranes servicing the loading and unloading of a ship.
The present invention is also particularly applicable to intermodal facilities for transferring shipping containers between different types of container shipping systems, such as between sea shipping transports, rail shipping cars, and roadway shipping equipment. In such intermodal facilities, containers are frequently unloaded, such as from a container ship, and placed into temporary storage prior to being loaded onto other container transportation equipment, which may be the same type such as a second container ship, or may be different such as railway shipping cars. The present invention relates primarily to a high density container storage yard system for the temporary storage of containers being transferred in such intermodal facilities.
2. Discussion of the Prior Art
The prior art discloses many similar types of container handling and storage systems, and also discloses many subsystems similar to those disclosed and taught herein. For instance, U.S. Pat. No. 3,952,891 discloses a stacking yard with containers stacked three high, a shore crane, and a plurality of container handling cranes which load and unload containers onto truck chassis from the stack locations. U.S. Pat. No. 3,559,822 discloses a similar concept having both a honeycomb silo and a stacking yard, and uses a gantry crane to move the containers from the yard to a conveyor system.
U.S. Pat. No. 3,543,953 discloses an overhead rail system for moving containers from shore cranes to honeycomb silos, and for moving containers from rail or truck unloading points to either the shore crane or the honeycomb silo. U.S. Pat. No. 3,091,188 also discloses an overhead rail system having shuttles which move containers from railway cars to a ship, or from trucks to a ship, or from trucks to the railway cars, or vise versa. This reference teaches storage of the containers in a warehouse, not in a high density storage yard. Both of these references are generally directed to silo systems which are quite different in concept and organization from the present invention.
Computerized systems for automatically handling and routing containers are disclosed in U.S. Pat. No. 3,952,891, U.S. Pat. No. 3,559,822, and U.S. Pat. No. 3,543,952. However, these prior art systems do not utilize an intelligent shuttle of the same general type disclosed herein.
Additionally, various types of shuttles intended for use on an overhead rail system are disclosed in U.S. Pat. No. 3,700,128 in which a shuttle is utilized to interface rail, truck, ship, air or transit terminals and storage media. This patent speaks of common storage areas and high-density buffer storage, but does not disclose a concept similar to a high density container storage yard. In this patent, shuttle cars operate on an overhead rail system which runs transverse to the storage of the containers, with mechanisms being provided for rotating and lifting the containers. This shuttle uses a pair of bogies, but they are not independently rotatable as in the present invention. It should also be noted that this reference discloses a communication system for an automatic computer controlled container handling system. U.S. Pat. No. 4,280,411 discloses a shuttle car having a pair of independently rotatable bogies which travel on an overhead rail while supporting a container. U.S. Pat. No. 3,956,994 also discloses a somewhat complex shuttle capable of carrying two containers simultaneously, and the shuttle car is suspended from an overhead rail system.
The present invention utilizes a switching mechanism carried by each of the shuttles to interact with an overhead rail to provide switching of the shuttle from one track to another at junction points. The prior art discloses similar switching mechanisms. For instance, Holt, U.S. Pat. No. 3,628,462 discloses a vehicle switching apparatus and several switches and switch operating mechanisms. In each disclosed embodiment, vertically reciprocating pistons are used to drive a pair of guide rollers upwardly to engage a guide rail fitted immediately adjacent the intersection. U.S. Pat. No. 3,780,666 discloses a variety of relatively complicated systems for use in a passive switching network. Both single rail and double rail embodiments are disclosed, including reciprocating rollers in connection with a unirail system and an overhead monorail, and reciprocating rollers which engage a guide surface. U.S. Pat. No. 3,830,163 discloses a suspended monorail having vertically reciprocating pistons which engage or disengage a guide rail. U.S. Pat. No. 4,498,399 discloses a pair of switch tracks with a single rotatable element. U.S. Pat. No. 4,094,252 discloses a monorail design with a single switching element. U.S. Pat. No. 3,815,510 discloses a switch design wherein the number of rolling tracks are reduced at a switch blade point four to three. U.S. Pat. No. 3,762,334 discloses a monorail switch having a pivoting switch blade. U.S. Pat. No. 3,760,739 discloses an active switch utilizing a linear induction motor for switching a switch vane or blade.
Container buffer systems are also known in the prior art, and U.S. Pat. No. 3,812,987 discloses a two level buffer mounted on a shore crane to provide a two level, two stage buffer. Incoming containers are loaded onto one stage of the buffer, while outgoing containers are loaded onto the other stage of the buffer. Transfer between the truck chassis and the incoming buffer is provided by an intermediate gantry crane having a stabilized hoist. Individual transport carts are used for conveyance. U.S. Pat. No. 4,018,349 discloses a two-stage, single level buffer with separate stages for loading and unloading. A shore crane is equipped with two separately movable gantries, one for off-loading from the supply buffer to the ship and a second for loading to and from ground level. U.S. Pat. No. 4,106,639 discloses a separate structure for use as a buffer which is positioned immediately adjacent a large gantry crane which removes the containers from the buffer and places them in a container storage yard. U.S. Pat. No. 3,543,952 discloses a monorail system for picking up containers from a shore crane, and delivering them to a horizontal or transverse accumulating buffer. U.S. Pat. No. 4,172,685 discloses a single stage, one way buffer for receiving containers from a shore crane and dispensing them to a secondary gantry crane. Alternately, the buffer can be used to accumulate containers as the vessel is loaded.
Although the prior art discloses components and subsystems similar to those employed by the present invention, the prior art does not disclose an overall system similar to the present invention which provides a highly efficient container storage and handling system for a high density container storage yard.